Evaluating An Algebraic Expression

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  • Опубліковано 14 жов 2024

КОМЕНТАРІ • 24

  • @eric314154321
    @eric314154321 2 місяці тому +3

    There is a MUCH easier way to do this.
    Cube both sides of the original equation.
    This gives x^3 + 1/x^3 =0
    Cube both sides again
    This gives x^9 + 1/x^9 = 0
    Multiply both sides by x^8 +1/x^8
    This gives x^17 + 1/x^17 +x +1/x =0
    Thus x^17 + 1/x^17 = - sqrt(3)

  • @miguelgnievesl6882
    @miguelgnievesl6882 2 місяці тому +1

    If we square (x+1/x) 3 times we get (x⁸+1/x⁸)=-1. We also cube it 2 times and get (x⁹+1/x⁹)=0. We multiply both expressions and the result is x¹⁷+1/x¹⁷=-√3.

  • @shmuelzehavi4940
    @shmuelzehavi4940 2 місяці тому +1

    Another approach
    The original equation is:
    x+1/x=√3
    By squaring this equation and simplifying we get:
    x^2+1/x^2 =1
    Therefore:
    x^4-x^2+1=0 ⟹ x^6=-1 ⟹ x^18=-1 ⟹ x^17=-1/x
    Therefore:
    x^17+1/x^17 =-1/x-x=-(x+1/x)=-√3

  • @stephenshefsky5201
    @stephenshefsky5201 2 місяці тому +3

    Syber's second method requires the leap of insight that sqrt(3) = 2*cos(pi/6). What if we just solve the original equation, a quadratic? We find x = (sqrt(3) +/- i)/2 = e^(i*pi/6), and the rest follows naturally.

  • @rakeshsrivastava1122
    @rakeshsrivastava1122 2 місяці тому

    Cubing both sides gives a neat result x^6=-1. x^17=(x^6)^3/x.

  • @scottleung9587
    @scottleung9587 2 місяці тому +1

    I used a third method, in which I found an expression for x^2, x^4, x^8, and x^16. Finally, I plugged in the expression for x^17 into the equation and set common denominators from there.

  • @Quest3669
    @Quest3669 2 місяці тому +1

    Made it complicated unessoryily.(.x^8+1/x^8)× (x^9+1/x^9) runs smooth

  • @maxgoldman8903
    @maxgoldman8903 2 місяці тому

    Another approach could be doubling the power of x:
    x² = √ 3 x - 1
    x⁴ = (x²)² = √ 3 x - 2
    x⁸ = (x⁴)² = 1 - √ 3 x
    x^16 = (x⁸)² = √ 3 x - 2
    x^17 = √ 3 x²- 2x = x - √ 3.
    x^17 + 1/x^17
    = x - √ 3 + 1/(x - √ 3) = -√ 3.

  • @maryamsiapouri9203
    @maryamsiapouri9203 2 місяці тому +1

    perfect❤❤❤

  • @phill3986
    @phill3986 2 місяці тому +1

    😊🎉😊👍👍👍😊🎉😊 glad your voice is coming back

  • @giuseppemalaguti435
    @giuseppemalaguti435 2 місяці тому

    x=e^(-iπ/6)...?=2cos(17π/6)=-2cosπ/6=-√3...mah,dovrei ricontrollare

  • @SidneiMV
    @SidneiMV 2 місяці тому +13

    x + 1/x = √3
    x² + 1/x² = 1
    (x² + 1/x²)(x + 1/x) = x³ + 1/x³ + x + 1/x
    √3 = x³ + 1/x³ + √3
    x³ + 1/x³ = 0
    x⁶ = -1
    x¹⁷ = (x⁶)³/x = -1/x
    1/x¹⁷ = -x
    *x¹⁷ + 1/x¹⁷ = -(x + 1/x) = -√3*

  • @allanmarder456
    @allanmarder456 2 місяці тому

    Let f(x) = x +1/x = sqrt(3) [f(x)]^2 =3 implies f(x^2)=1 f(x)*f(x^2) = sqrt(3) implies f(x^3)=0 f(x^3)*f(x^6) = f(x^9) +f(x^3) =0 implies f(x^9)=0
    f(x^9)*f(x^8) = f(x^17) + f(x) thus f(x^17) = f(x^9)*f(x^8) - f(x) = 0*f(x^8) -sqrt(3) = -sqrt(3)

  • @9허공
    @9허공 2 місяці тому +1

    (x + 1/x)^3 =x^3 +1/x^3 + 3x*1/x*(x + 1/x)
    3√3 = x^3 + 1/x^3 + 3*√3 => x^3 + 1/x^3 = 0 => x^6 = -1
    x^17 = x^18 / x = (-1)^3 / x = -1/x => 1/x^17 = -x
    x^17 + 1/x^17 = -1/x - x = -(x + 1/x) = -√3

  • @tetsuyaikeda4319
    @tetsuyaikeda4319 2 місяці тому

    your voice was depressive recent day

  • @yogamulyadi2046
    @yogamulyadi2046 2 місяці тому

    x=½(√3]±i)=e^±⅓πi
    ?=e^⅓πi+e^-⅓πi=1

  • @赖皮球
    @赖皮球 2 місяці тому

    x^2+1/x^2=1 x^4-x^2+1=0 (x^2+1)(x^4-x^2+1)=0=(x^6+1) x^6=-1 x^6=-1 x^17+1/x^17=x^18/x+x/x^18=-1/x-x=-(x+1/x)=-sqrt(3)

  • @Marcus-y1m
    @Marcus-y1m 2 місяці тому +4

    This explanation is too unclear. Please be more accurate. We All need to learn and we Are not in the same level of understanding. Sorry for being this honest. thanks for your work

    • @SidneiMV
      @SidneiMV 2 місяці тому +5

      @@Marcus-y1m x + 1/x = √3
      x² + 1/x² = 1
      (x² + 1/x²)(x + 1/x) = x³ + 1/x³ + x + 1/x
      √3 = x³ + 1/x³ + √3
      x³ + 1/x³ = 0
      x⁶ = -1
      x¹⁷ = (x⁶)³/x = -1/x
      1/x¹⁷ = -x
      *x¹⁷ + 1/x¹⁷ = -(x + 1/x) = -√3*

    • @SidneiMV
      @SidneiMV 2 місяці тому +1

      @@Marcus-y1m x + 1/x = √3
      x² + 1/x² = 1
      (x² + 1/x²)(x + 1/x) = x³ + 1/x³ + x + 1/x
      √3 = x³ + 1/x³ + √3
      x³ + 1/x³ = 0
      x⁶ = -1
      x¹⁷ = (x⁶)³/x = -1/x
      1/x¹⁷ = -x
      *x¹⁷ + 1/x¹⁷ = -(x + 1/x) = -√3*

    • @TGrod
      @TGrod 2 місяці тому +1

      ​@@SidneiMV wow, it was perfect!

    • @Marcus-y1m
      @Marcus-y1m 2 місяці тому +2

      Thanks for helping. Now i got it.